Hydraulic pump for liquids



May 22, 1945. R. J. HARDEY HYDRAULIC PUMP FOR LIQUIDS Filed Nov. 14, 1944 INVENTOR.

Patented May 22, 1945 UNITE STATES PATENT OFFICE 4 Claims.

This invention aims to provide novel means whereby the weight of a column of fluid in a vertically-acting piston pump may be ofiset by the weight of fluid in a vertical fluid-pressure line, thereby to provide approximate piston balance, means being provided for putting operating pressure on the fluid in the fluid pressure line, to secure actuation of the piston. Another object of this invention is to supply structural details for carrying out the aforesaid operation, and other operations auxiliary thereto.

r A mechanic who abides by what is claimed, may

make such changes as his skill may direct, without departing from the spirit of the invention.

In the drawing, the device is disclosed in a single figure which, for the major part, is a vertical section.

The letter L marks a substantially vertical, lower pump cylinder, and the letter U designates a substantially vertical upper pump cylinder, aligned axially with the lower pump cylinder. The pump cylinders L and U are shown as integrally formed, but that construction need not he insisted upon. The individuality of the cylinders L and U is maintained by a partition I in the tubular, vertical member of which the cylinders L and U form parts, the partition preferably being a stufling box.' The upper cylinder U is supplied with one Or more lateral vents 2, located above and in close vicinity to the partition I.

The numeral 3 designates a vertical discharge conduit. The lower end of the discharge conduit 3 communicates with the lower cylinder L at a place below the partition I, but in close relation to the partition. The upper end of the discharge conduit 3 communicates with the upper cylinder U at a place spaced vertically above the partition I. A downwardly closing check valve 4 is interposed in the discharge conduit 3 and is located near the partition I.

At S'there appears a dependinginlet for the lower cylinder L. The inlet 5 communicates with the cylinder L at a place below the partition I and below, but close to, the lower end of the discharge conduit 3. A downwardly closing check valve.v 6 is interposed in the inlet a and is located near the upper end of the inlet.

An upper pump piston 'l is mounted for reciprocation in the upper cylinderU. A lower pump piston 8 is mounted for reciprocation in the 5 lower cylinder L. The pistons-1 and 8 are joined by a rod connection 9, mounted to reciprocate in the partition I. The-inlet 5 communicates with the cylinder L at a place well. above the lower piston 8, when that pistonis at the limit of its downward travel. An abutment ring 31 is mounted fixedly in the upper cylinder U. A compression spring 21 is interposed between the abutment ring 3i and the upper piston l.

The upper end of the upper cylinder U is supplied with an outlet ill. The lower end of the lower cylinder L is joined by a bend ill to the lower end of a vertical fluid pressure line i2,

connected at its upper end with a master or fluid pressure cylinder M, shown as disposed horizontally, the position of' said cylinder being optional.

A gland i5 is mounted on one end of the cylinder M. A power operated piston rod l6 reciprocates in the gland iii. The piston red It carries a master piston ll, slideably mounted in the cylinder M.

The numeral i8 designates a tank, adapted to contain the actuating fluid, the tank being located above the cylinder M. The tank it has a filling closure l9. Communication between the tank I8 and the cylinder l4 isestablished by spaced connections 20 and 2!. The connection 2| is located adjacent to the gland l5. The eonnection 20 is remote from the gland [5.

As to gross operation, when the piston ll moves to the right, suction is created in the cylinder M, the fluid pressure line l2 and the bend II, the upward pressure on the piston 8 being re- .lieved, and that piston being caused to move downwardly. The check valve 4 closes, the check valve '6 opens, and liquid enters the cylinder L through the inlet 5.

When the piston I'I moves tothe left, pressure is created in the cylinder M, the fluid pressure line 12 and the bend ll, upward pressure being exerted upon the piston 8, that piston sure on the piston 8, and the piston structure a 1-8 remains approximately balanced at all times. The function of the-spring 21 is to supplement the eifect of the head on the piston I, and to aid in returning the piston structure 1--8 to.the lowered position shown in the drawing, against the upward pressure of the actuat ins fluid in the pressure'line l2, on the piston 8.

The vents 2 promote an easy movement of the piston 1.

A concrete example will promote a clear understanding of the device. Suppose that two open strings of pipe (IO-l2) are run into a hole, to a depth of several thousand feet, the strings being connected at their lower ends by'the fbend ll. Assume that both strings are filled with liquid. By applying a small amount of pressure at the top of the liquid in one string (l2), the liquid will be caused to emerge [from the topof the other string (l) Assume that the device is installed three thousand feet deep in an oil well, and that the spring 21 exerts a pressure of ten pounds per square inch on top of the piston I. The outlet line I0 is filled with oil, and actuating fluid is in place in the string 12-. The pressure on top of the piston 1 is 3000x334, plus (depth of well times pressure per square inch of oil one foot in depth, plus spring pressure), or a total of 1012 pounds.

The pressure in the string l2l l is 1004 pounds, beneath the piston 8 (assuming a distance of 6 feet from the bottom of the piston 8 to the top of the piston 'l). The aforesaid difference in pressures, 1012 pounds less 1004 pounds, or 8 pounds, would cause the piston structure 1-8 to assume the lowered position depicted in the drawing. If a pressure of 8 pounds were exerted in the string I 2| I, by the master piston I'I in the master cylinder 14, the two pressures will be balanced and any additional pressure effected by the piston I! will cause the piston structure 1-8 to move upwardly, iorcing liquid in the cylinder L to pass through the conduit 3 and the outlet When the piston ll moves to the right, the pressure beneath the piston 8 is lessened, and the weight of the liquid on the piston 1, which weight is held in the outlet 10 by the check valve 4, plus the pressure of the spring 21, exerts suflicient efiort on the top of the piston I to cause the piston structure 1-8 to return to the lowered position shown. A fresh supply of liquid enters the cylinder L by way of the inlet 5, and the cycle is completed.

The actuating fluid functioning below the piston 8 may be the same as the fluid pumped, but if there is a difierence in the fluids, compensation may be aflorded by changing the spring 21.

Considered structurally, the advantages of the device will be appreciated by those skilled in the art. They include a minority of parts, resulting in smallinstallation costs and decreased charges for up-keep and operation.

What is claimed:

1. In a pumping mechanism, separate, substantially vertical upper and lower cylinders, the

upper cylinder having an upper outlet, 9. discharge conduit communicating with the upper portion of the lower cylinder and with the upper cylinder at a place below the outlet, an inlet communicating with the upper portion or the lower cylinder, a downwardly closing check valve in the inlet and a downwardly closing check valve in the discharge conduit, an upper piston slidable in the upper cylinder below the upper end of the discharge conduit, a lower piston slidable in the lower cylinder, a connection uniting the pistons, a substantially vertical fluid pressure line communicating with the lower portion of the lower cylinder at a place below the lower piston, and power-driven means spaced from the cylinders and the outlet, and exerting operating pressure on the fluid in the fluid pressure line, exclusively.

2. In a pumping mechanism, separate, substantially vertical upper and lower cylinders, the upper cylinder having an upper outlet, 9. discharge conduit communicating with the upper portion of the lower cylinder and with the upper cylinder at a place below the outlet, an inlet communicating with the upper portionof the lower cylinder, a downwardly closing check valve in the inlet and a downwardly closing check valve in the discharge conduit, an upper piston slldable in the upper cylinder :below the upper end of the discharge conduit, a lower piston slidable in the lower cylinder, a connection uniting the pistons, a substantially vertical fluid pressure line communicating with the lower portion of the lower cylinder at a place below the lower piston, means for exerting operating pressure on the fluid in the fluid pressure line, a compression spring located in the upper cylinder and exerting downward thrust on the upper piston, and an abutment in the upper cylinder and receiving the upward thrust of the spring.

3. In a pumping mechanism, separate, substantially vertical upper and lower cylinders, the upper cylinder having an upper outlet, a discharge conduit communicating with the upper portion of the lower cylinder and with the upper cylinder at a place below the outlet, an inlet communicating with the upper portion of the lower cylinder, a downwardly closing check valve in the inlet and a downwardly closing check valve in the discharge conduit, an upper piston slidable in the upper cylinder below the upper end of the discharge conduit, a lower piston slidable in the lower cylinder, a connection uniting the .pistons, a substantially vertical fluid pressure line communicating with the lower portion of the lower cylinder at a place below the lower piston, and means for exerting operating pressure on the fluid in the fluid pressure line, the means for exerting downward pressure on the fluid in the fluid pressure line comprises a, master cylinder connected to the upper portion of that line, and a master piston mounted to reciprocate in the master cylinder.

4. In a pumping mechanism, separate, sub-' stantially vertical upper and lower cylinders, the upper cylinder having an upper outlet, a discharge conduit communicating with the upper portion of the lower cylinder and with the upper cylinder at a place below the outlet, an inlet communicating with the upper portion of the lower cylinder, a downwardly closing check valve in the inlet and a downwardly closing check valve in the discharge conduit, an upper piston slidable in the upper cylinder below the upper end of the discharge conduit, a lower piston slidable in the lower cylinder, a connection uniting the pistons, a substantially vertical fluid pressure line communicating with the lower portion of the lower cylinder at a place below the lower piston, and means for exerting operating pressure on'the fluid in the fluid pressure line, the means for exerting downward pressure on the fluid in the fluid pressure line comprises a master cylinder connected to the upper portion of that line, and a master piston mounted to reciprocate in the master cylinder, a tank for pressure fluid, and connections communicating with the tank, and with the master cylinder at places spaced longitudinally of the travel of the master piston.

' RODNEY J. HARDEY. 

